D7000 in cold weather

I'm heading for northern Minnesota later this week and I could use some advice on cold weather shooting. I'll be using my D7000 with a Sigma 17-50 and a Nikon 18-140. The temperatures are likely to range between -5 and +20. Other than making sure I have fully charged batteries, are there any particular things to do to protect the camera and lenses?

For example, I read years ago that bringing the camera straight into a warm building from outside could cause condensation to appear inside the lens. True or false? Other thoughts about taking care of the gear? Thanks in advance for replies.